Foam pump



Feb. 12, 1957 Filed Dec. 30, 1955 D. F. THOMAS EI'AL 2,781,000

FOAM PUMP 2 Sheets-Sheet Al ATTORNEY Feb. 12, 1957 p. F. THOMAS EI'AL 2,781,009

FOAM PUMP Filed Dec. 30, 1955 2 SheetsShee 2 127/ I Z I INVENTOR Da /d F Thoma-s fiolwf A. /7/'// BY QM ATTORNEY pump.

ited States Patent FOAM PUMP David F. Thomas, est St. Paul, and Robert A. Hill, Minneapolis, Minn, assignors 'to Waterous Company, St. Paul, Minn., a corporation of Minnesota Application December 39, 1955, Serial No. 556,718

7 Claims. (Cl. 103-136) This invention relates to an improvement in foam pumps and deals particularly with a pumping apparatus useful in producing foam used in combating fires.

Various types of foam pumps have been produced. These pumps usually include an inlet for the foam producing liquid and an inlet for air. The inlets are so arranged that a mixture of air and liquid is drawn into the pump. The liquid and air are thoroughly mixed, producing a foam which is forced through a suitable screening device to an outlet. In certain instances these pumps have been of the type involving a rotor having radially extending vanes slidably supported thereon.

While pumps of this type have been successfully produced, there have been certain features which have been considered disadvantageous. in the first place, many such pumps include circumferential ribs which hold the vanes from outward movement as the vanes near the pump outlet and which act to retract the vanes as they move past the outlet. These ribs contact only predetermined portions of the vanes. As a result the vanes wear unevenly due to contact with these ribs during the retracting operation, thereby causing grooves to be formed in the free end of the vanes. It is desired to eliminate this difliculty in the present invention.

Another feature of difliculty with pumps of this type lies in the fact that difficulty is sometimes experienced in inspecting the rotor vanes at regular intervals. A rotary pump of the vane type normally must be supported by bearings located at opposite ends of the pump. As a result the inspection of the vanes normally involves the removal of an end plate of the pump and removal of the supporting bearings at the outboard end of the It is an object of the present invention to avoid this previous difficulty.

A further difliculty which has been experienced with pumps of the type in question lies in the fact that the vanes are usually difiicult to remove and replace. It is an object of the present invention to avoid this previous difficulty.

A feature of the present inventionlies in the provision of a vane pump having ribs which act to retract the vanes and which are spiral in form. As a result the rotation of the vanes about the center of the rotor causes a successively diiferent portion of the rib to engage the vane during retraction, thereby considerably decreasing the wear upon the ends of the vanes'during the retraction thereof.

An added feature of the present invention resides in the provision of an inspection port in an end of the pump. This inspection port may be quickly and easily removedfor the inspection of the vanes. As the port is located to extend substantially to the periphery of the vanes, the ends of the vanes can be quickly inspected for wear and the like.

A further feature of the present invention resides in the fact that the inspection port may serve" as a means of removing the vanes from the pump; In the preferred "ice 2 form, one inspection port may be located on each end of the pump so that the vanes may be withdrawn from their grooves in the rotor and inspected or repaired.

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification:

Figure l is an elevational view of the pump.

Figure 2 is a cross sectional view through the pump showing the arrangement of parts therein.

Figure 3 is a sectional view through the pump, the position of the section being indicated by the line 3-3 of Figure 2. I

The pump is indicated in general by the letter A and includes a generally cylindrical housing 10. On one side of the housing an intake passage 11 extends, with its lower walls substantially tangent to the bottom of the housing. The upper wall 12 of the intake port or passage extends parallel to the lower wall '13 thereof and is shown as slightly below the center of the housing.

The intake passage 11 communicates with a suction chamber 14 including a bottom panel 15, a Wall panel 16, and an upwardly and outwardly inclined top panel 17. The outer extremity of the upwardly and outwardly inclined panel 17 extends horizontally, as indicated at 19. The ends of the suction chamber are closed by end plates 20 having cylindrical inlet openings 21 therein. The inlet openings may be closed by closure caps or plates 22 or may be provided with similarly shaped flanges which permit connection with a suction pipe or the like.

The panel 16 of the suction chamber is provided near its upper extremity with an aperture 23 having a' screen 24 or other foraminous member supported therein. The aperture 23 forms the air intake port and the screen 24 serves to screen the air entering the inlet of the pump. A cylindrical screen 25 is supported between the inlet openings 21 so that incoming fluid must flow into the interior of the screen tube and must pass through the screen to enter the remainder of the suction chamber. A pair of ribs 26 form a continuation of the inner cylindrical surface 28 of the pump housing 10 overlying the intake passage 11. These ribs 26 are parallel in most constructions but may if desired extend spirally in the manner of the ribs overlying the pump outlet if such construction is preferred.

The pump housing is closed at opposite ends by end closure plates 27 and 29 which are bolted or otherwise afiixed peripherally to the pump body. Bolts or cap screws such as 30 and 31 extend through the closure plates and into threaded openings in peripheral flanges 32 and 33 at opposite ends of the pump housing 10.

The closure plate 27 is provided with an outwardly projecting flange 34 which is supported by various radially extending reinforcing ribs 35 and 36. The flange 34 is designed to accommodate a bearing mounting plate 37 which is secured thereto in any suitable way. In Figure l of the drawings, cap screws 39 are shown for bolting the mounting plate 37 to the flange 34. The bearing supporting plate 37 is provided with a' cylindrical axial aperture 40 extending therethrough which accommodates the outer race 41 of an anti-friction bearing 42. The inner race 43 of the bearing 42 encircles the outboardend 44 of the rotor shaft 45. The bearing 42 is held in place by any suitable means. A sleeve'46 is shown encircling the end 44' of the shaft 45, the sleeve 46' being slightly" spaced from a shoulder 47' between the shaft end- 44 and" the center portion of thisshaft. A ring 49 is interposed between the outer end of the sleeve and the inner race 43' of the bearing 42. A nut 50 is threaded onto the outer end of the shaft portion 44 and is held in locked condition by a suitable locking ring 51-. A cap plate'52.

is provided with an axial aperture 53 designed to accommodate the small diameter extremity 54 of the shaft 45 and this plate is secured to the bearing supporting plate 37 by bolts 55 or other suitable means. A sealing ring construction is provided between the flange 56 at the end of the sleeve 46 and the end plate 27 of the pump. This seal includes a plurality of sealing elements which operate together to form an effective fluid type seal between the rotating shaft portion 44 and the end plate 27. The flange56 is clamped against the end face of a counterbore 48 in the rotor hub 94, and a gasket 56 is interposed between these parts to prevent leakage of liquid to the shaft.

The end plate 29 also includes an outwardly projecting ring-shaped flange 57 to which is bolted the side plate 59. of the transmission housing 60. The side plate 59 includes at its outer periphery a peripheral flange 61 which encircles the transmission gears and which is provided at its free end with'an outwardly extendingperipheral flange 62. The transmission closure plate 63 is bolted to the flange 62 to form a closure for the transmission housing. The position of such bolts may be indicated by the numeral 64.

The transmission side plate 59 is provided with an aperture 65 extending therethrough in which is inserted the outer race 66 of an anti-friction bearing 67. The inner race 69 of the bearing 67 encircles the end 70 of the rotor shaft 45. The shaft end 70 is preferably slightly smaller in diameter than the center portion of the shaft 45 and a sleeve 71 having a peripheral flange 72 at an end thereof is spaced slightly from the shoulder between the small diameter shaft portion and the central portion of the shaft. The flange 72 is clamped against the face of a counterbore 68 in the rotor hub 94, a gasket 72 being interposed between these parts to prevent leakage of liquid to the shaft.

A seal 73 encircles the sleeve 71 and forms an effective seal between the rotating shaft 45 and the end plate 29 of the pump. The details of the seal are not described, as the. details of the seal form no part of the present invention.

A bearing supporting cap 77 includes a cylindrical sleeve 79 on one side thereof which extends into an opening'80 in the transmission side plate 59. The sleeve 79 forms a support for the outer race of an anti-friction hearing 81. The inner race of this hearing encircles the drive shaft 82 for rotatably supporting the same.

A second bearing 83 is supported in an aperture 84 formed in the closure plate 63 of the transmission housing. The bearing 83 encircles the outwardly projecting end 85 of the drive shaft 82.

A gear 86 is supported upon the end 70 of the rotor shaft 45 and is keyed or splined thereto. A pinion 87 is provided on the drive shaft 82 between the ends thereof. The gears 86 and 87 are in mesh so that rotation of the drive shaft 82 will cause rotation of the rotor shaft 45.

The rotor is indicated in general by the numeral 90 and is best illustrated in Figure 3 of the drawings. The rotor 90 includes a hollow cylindrical shell 91 having angularly spaced slots 92 therein. The slots 92 are provided within radially extending spokes 93 which connect the cylindrical rim 91 with the central hub 94. The hub 94 is supported upon the rotor shaft 45 and is rotatable in unison therewith.

The shaft 45 is eccentrically positioned with respect to the rotor housing 10. The center or axis of the shaft 45 is offset toward the extremity of the discharge mani fold 95 which is approximately 210 from the inlet passage 11. The rotor housing flares away from the inner cylindrical surface of the housing from a point approximately 90 from the inlet. In other words, the rotor chamber expands in size as the rotor vanes are retracted. Ribs 96 are provided bridging the outlet manifold 95, these ribs 96 being spiral in form. As is indicated in Figure 2 of the drawings, the ribs 96 are wide the ribs 26 guide the outer ends 101 of the vanes to fully projected position. Fully projected position of the vanes is at an angle of perhaps 90 from the center of the f intake opening.

After the vanes 100 pass the intake passage 11, they are guided outwardly to fully projected position by the cylindrical inner surface of the housing 10. This surface continues for an additional 40 to 45 on the point 102 a where the rotor housing flares away from the cylindrical inner surface of the ribs 96.

The outlet manifold 95 is provided with a peripheral flange 103. A bell-shaped discharge manifold member 104 is provided with an end flange 105 which fits against the'flange 103 and is bolted or otherwise secured thereto. This bell-shaped housing 104 is provided with a counterbored portion 106 which acts to support the rims 107 of a series of screens 109. These screens are designed to break up the flow of fluid and to assist in the production of foam.

, respective end plates by bolts 112. The ports 110 are coextensive in length or are of slightly greater diameter than the length of the vanes 100. Accordingly, any of the vanes 100 may be removed by forcing the same laterally through the inspection port.

As is indicated in Figure 2 of the drawings, the inner surface of each cover plate 111 is flush with the inner surface of the housing end plate in which it is situated to form a continuation of the housing wall. 'Each cover plate is provided with an outwardly directed flange 113' extending partially about the circumference of the opening so as to limit the inward insertion of the cover plate and to maintain the inner surface of the cover plate flush with the inner surface of the end plate.

The operation of the apparatus should be apparent from the foregoing description. The drive shaft 82 has its projecting end connected to a suitable source of.

driving power. Rotation of the drive shaft 82 acts through the gears 87 and 86 to drive. the rotor shaft 45 and the rotor mounted thereon.

Rotation of the rotor in. a clockwise direction, as

viewed in Figure 3, acts to draw fluid from one or both of the openings 21, this liquid passing through the cylindrical screen 25 as it enters the intake chamber 20. The liquid entering the pump is usually water mixed with I a foaming agent capable of creating foam. Air is also drawn into the pump through the screen 24 located at the top of the intake chamber 20.

The combined air and liquid are drawn into the lower side of the pump by the expansion of the space rearwardly of each vane as the vanes rotate. The vanes are spaced so that one vane starts its movement over the intake as the next advanced vane passes the intake passage. The air and liquid between each pair of successive vanes is confined between the. vanes for but a short space of time during which the vanes are near their outer limit of movement. 1

As each vane passes the point 102 where the casing tapers away from the rotor housing, the mixture of air and liquid is allowed to escape between and around the ribs .96 and into the outlet port 95. The product then passes through the series of screens 109 where it is more intimately broken up and the foam thus produced is forced through the outlet end 114 of the bell-shaped housing 104.

The spiral shape of the is desirable as the ribs 96 form the surface which acts to retract the vanes 190. If the ribs 96 were parallel in position, constant rotation of the rotor would cause the portions of the vanes contacting the ribs 96 to become grooved. As a result the ends of the vanes would not fit snugly against the cylindrical inner surface of the pump housing 10. As the ribs 96 are spirally formed, the part of the vane engaged by the ribs changes constantly so that the ribs must wear evenly.

With reference to Figures 2 and 3 of the drawings it should be noted that a series of angularly spaced inwardly projecting lugs 115 are provided near each end of the rotor 90. When cast and machined the rotors are often not accurately balanced. In order to balance the rotor, any required number of lugs 115 may be broken off in order to effect proper balance. This arrangement prevents the necessity of drilling or grinding away metal or adding weights to the rotor when balancing. This feature is believed novel and advantageous. The lugs 115 are connected to the rotor by relatively small necks 116 or areas of connection, to simplify the removal of selected lugs.

The provision of the inspection ports which may he opened to inspect or remove the vanes, is of importance as these ports eliminate the necessity of disassembling the entire side of the pump for this purpose. if the in spection ports were not provided it would be necessary to remove the entire end plate' of the pump including the outboard bearing and part of the pump seal. This work is eliminated in the present construction.

In accordance with the patent statutes, we have described the principles of construction and operation of our foam pump, and while we have endeavored to set forth the best embodiment thereof, we desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of our invention.

We claim:

1. A foam pump including an inlet chamber having a liquid inlet port and an air port, a rotor housing communicating with said intake chamber to receive liquid and air therefrom, a. rotor within said housing, means rotatably supporting said rotor eccentrically with respect to the axis of said housing, vanes slidably supported in said rotor, said vanes having outer ends slidable against the inner surface of said housing, an outlet passage in said rotor housing, and rib means bridging said outlet passage, the inner surface of said rib means forming a continuation of the inner surface of said rotor housing against which the outer ends of the vanes engage for retraction, said rib means extending spirally across said outlet passage.

2. The construction described in claim 1 and including rib means bridging said inlet passage and against which said vanes may engage.

3. The construction described in claim 1 and including port openings in the ends of said rotor housing located opposite the path of the slidable vanes and spanning the length of any vane which moves into a position opposite the port openings, said port openings being of suflicient size to permit removal of said vanes therethrough, and closure plates normally closing said ports.

4. A vane pump including an inlet chamber having a liquid inlet port and an air port, a rotor housing communicating with said intake chamber to receive liquid and air therefrom, a rotor within said housing, vanes slideably supported in said rotor, said vanes having outer ends slideable against the inner surface of said housing, an outlet passage in said rotor housing, :rib means bridging said outlet passage, the inner surface of said rib means forming a continuation of the inner surface of said rotor housing against which the outer ends of the vanes engage for retraction, port openings in the ends of said rotor housing located opposite the path of the slideable vanes and spanning the length of any vane which moves into a position opposite the port openings, said port openings being of suificient size to permit removal of said vanes therethrough, and closure plates normally closing said ports.

5. The structure of claim 4 and in which said rib means extend spirally across said outlet passage.

6. A foam pump including an inlet chamber having an inlet opening, an air opening in said inlet chamber above the level of said inlet opening, a rotor housing, an inlet passage connecting said inlet chamber with said rotor housing, a rotor eccentrically supported for rotation within said housing, vanes slideably supported by said rotor for radial movement with respect thereto, an outlet port in said housing, said rotor extending substantially tangent to the inner surface of said housing at a point between said discharge port and said inlet passage and adjoining said discharge port, said housing flaring away from the cylindrical inner surface of said rotor on the other side of said discharge port forming said point of tangency, ribs bridging said discharge port and the flaring portion of said housing, and screen means in said discharge port through which fluid is forced by said vanes, said ribs extending spirally across the discharge port.

7. A foam pump including an inlet chamber having an inlet opening, an air opening in said inlet chamber above the level of said inlet opening, a rotor housing, an inlet passage connecting said inlet chamber with said rotor housing, a rotor eccentrically supported for rotation within said housing, vanes slideably supported by said rotor for radial movement with respect thereto, an outlet port in said housing, said rotor extending substantially tangent to the inner surface of said housing at a point between said discharge port and said inlet passage and adjoining said discharge port, said housing flaring away from the cylindrical inner surface of said rotor on the other side of said discharge port forming said point of tangency, ribs bridging said discharge port and the flaring portion of said housing, and screen means in said discharge port through which fluid is forced by said vanes, said ribs being widely spaced at one end and converge together at their other end.

References Cited in the file of this patent UNITED STATES PATENTS 1,074,792 Hunt Oct. 7, 1913 1,296,500 Frodsham Mar. 4, 1919 1,439,365 Hazell Dec. 19, 1922 1,455,252 Jackson May 15, 1923 1,989,864 Jaworowski Feb. 5, 1935 2,174,869 Czarnecki Oct. 3, 1939 2,543,447 Elrod Feb. 27, 1951 2,741,992 Glazebrook Apr. 17, 1956 2,760,383 De Moss Aug. 28, 1956 FOREIGN PATENTS 592,452 Great Britain Sept. 18, 1947 608,794 France Apr. 30, 1926 699,357 Great Britain Nov. 4, 1953 

